The present invention is related generally to medical devices. More specifically, the present invention includes intravascular devices and catheters for performing endarterectomy.
Arteriosclerosis is a common vascular disease in which blood vessels become hardened and blocked or partially blocked by plaque that can substantially reduce blood flow. The accumulation of plaque is often a major factor in the occurrence of myocardial infarction, stroke, and high blood pressure.
To treat arteriosclerosis, minimally invasive techniques have been developed. One minimally invasive technique utilizes percutaneous transluminal coronary angioplasty (PTCA) which can include expanding a balloon under pressure within a coronary artery, and dilating a narrowed area of that artery. While PTCA procedures can significantly dilate narrowed coronary arteries, the treated vessel region may become narrow again in a process known as restenosis. In a substantial percentage of PTCA procedures, the dilated vessel region becomes restenosed.
Another example of a minimally invasive technique is atherectomy. In an atherectomy procedure, a guide catheter can be inserted into the patient""s femoral artery and advanced until the distal end of the guide catheter is disposed near the patient""s ostium or coronary artery. A guidewire can be inserted into the guide catheter and further advanced into the coronary artery, distally past the occluded region. A therapeutic atherectomy catheter having an atherectomy burr may be advanced over the guidewire, through the guide catheter, and to the narrowed region. The atherectomy burr can be rotated at high speed, causing the plaque to be removed in small particles as the plaque is abraded by the atherectomy burr.
Endarterectomy techniques have been utilized in open chest surgeries. In the endarterectomy technique, an artery may be slit longitudinally along its length by a surgeon, commonly after clamping opposite ends of the exposed vessel. The surgeon may strip the internal plaque away from the vessel walls, and remove the plaque from the vessel through the slit. A significant cleaning procedure typically follows the removal procedure to increase the chance of success. In a high percentage of cases, the vessel thus treated may remain potent for a long time period, rather than rapidly becoming restenosed.
What would be desirable are endarterectomy techniques and devices for performing endarterectomy intravascularly. In particular, what would be advantageous are techniques for performing intravascular endarterectomy using a distant entry site, such as a radial artery entry near the groin.
The present invention includes methods and devices for removing plaque and separating plaque from blood vessels using everting membranes. In one method according to the present invention, an everting membrane is provided and distally advanced through a vessel having a plaque deposit along the vessel wall. The everting membrane may be considered to have a distally advancing portion, a distally leading edge, and a non-advancing portion, where the advancing portion is distally advanced into the vessel. As the advancing portion is distally advanced into the vessel, the leading edge is distally advancing into the vessel as well. As the advancing membrane portion and leading edge are advanced into the vessel along the vessel inner wall, the everting membrane advances between the plaque and the vessel inner wall, thereby separating the plaque from the inner wall. The non-advancing portion can be effectively laid down over either the vessel inner wall or plaque outer walls, depending on orientation. After separation, the separated plaque may be removed from the vessel.
One device according to the present invention has a tubular member having a single everting membrane, the membrane having an interior in fluid communication with a fluid source. The fluid may be supplied through a fluid lumen, thereby supplying the everting membrane interior with fluid under pressure. The pressurized fluid may then cause the everting membrane to travel distally. The distally traveling membrane leading edge may be used to separate the plaque from the vessel inner wall. In one embodiment of the invention, the everting membrane has a more proximal section slidably and sealingly disposed along the tubular member inner wall.
One double everting membrane device according to the present invention includes an inner tube and an outer tube, with the inner tube having an inner fold and the outer tube having an outer fold. The inner and outer folds may be joined and/or simply travel together at a more proximal location. The inner and/or outer folds preferably have interior portions which may be provided with fluid under pressure, thereby causing the inner and outer folds to travel distally. The inner and outer folds may be considered to have facing advancing portions, leading edge distally advancing portions, and relatively non-advancing portions which will unfold and be laid down against the vessel inner wall and the outer wall of the newly separated plaque. The pair of everting membranes may thus be deployed to separate the plaque from the inner wall. After separation, the everted membranes having the plaque disposed within the inner fold may be removed from the formerly constricted vessel site.
Everting membranes in some methods according to the present invention may be used in conjunction with more distally positioned emboli filters. The deployed emboli filters may provide additional assurance of optimal results during the treatment. In one method, the emboli filter and percutaneous endarterectomy catheter are advanced over a guidewire positioned within the coronary artery from a femoral groin entry site. The present invention allows the stripping or removal of plaque from within coronary and other arteries using an intravascular device, not requiring open chest surgery.